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Solve the following simultaneous equations.

• $2x + 3y = 15$
• $4x + 5y = 20$
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multiply eqn 1 by 2

4x + 6y=30

4x +5y=20 then eliminate by subtracting  eqn 2 from 1

y=10, substitute into any original eqns

2x + 3(10)=15

x= -7.50
by Diamond (84.9k points)
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2x + 3y = 15

4x + 5y = 20

multiply first line by 2:

2(2x +3y =15)

4x +6y = 30

subtract the second line from the first line to find (y):

(4x + 6y = 30) - (4x + 5y = 20)

y = 10

solve for both equations:

2x + 3(10) = 15

2x = 15 -30

x = -7.5

4x + 5(10) = 20

4x = 20 - 50

x = -5

conclude:

y = 10

x1 = -7.5

x2 = -5
by Wooden (1.5k points)

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